Telephone-connecting apparatus.



E. G. MOLIN'A. TELEPHONE GONNBGTING APPARATUS.

APPLICATION FILED JUNE 19, 1907.

Patented July 6, 1909.

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: UNITED STATES PATENT oFFIoE.

EDWARD O. MOLINA,-OF ARLINGTON, MASSAGJIIZU SE'I TS, ASSIGNOR TOAMERICAN TELEPHONE AND TELEGRAPH COMPANY, AICORPOE ATION OF NEW YORK.

TELEPHONE-CONNECTING APPARATUS.

Patented July 6, 1909.

Application filed June 19, ,1907. Serial No. 379,803.

To all whom it may concern:

Be it known that I, EDWARD (J. lVlOLINA, residing at Arlington, in thecounty of MiddleseX' and State of Massachusetts, have invented certainImprovements in Telephone- Qonnecting Apparatus, of which the followingis a specification. The number assigned to a telephone subscriber may beeither that of a single line, as

one connecting a central station with the usual substation, or it maybethat'be'longing to the first of a group of trunk lines which extendfrom the central station to the switch apparatus of a private branchexchange, such as is often installed for subscribers using severalinstruments. In manual practice the operator upon receiving a call for asingleline substation needs only to test the proper jack in themultiple, and either complete the connection'and ring the calledsubscriber or notify the calling subscriber that the line is busy, andremove the plug from theanswering j ack. If the call is for a privatebranch exchange the operator must, as its trunks are found to hem use,successively test the remainder until an idle one is reached, or, if theentire group is busy, so inform the calling subscriber. In systems inwhich mechanical switching apparatus is employed these acts of theoperator, varying according to "the class of service for which the linesare adapted, must have their analogue in the opera.

tions of the connector or final selector. That is, when the movablecontact members reach the terminals of the desired single line,

they must either, when this is idle, unite with and ringover it, or,when in use, apply a busy signal and restore the apparatus to its normalcondition; while, if the call is to a private branch exchangehaving aplurality of llIlOS, these must be successively tested until an ldlc one=1s i'ound, or until the last trunk is reached, and if this is employed,

' bringtlie busy signal into play andrelease connector in the chain ofselectingapparatus, and a selection controlling means conventionallyrepresented.

The final selecting or connecting switch S,

which I .have chosen to illustrate as a part of the organization, is ofthat familiar type in which a rotatable shaft 8 carries insulated fromit movable contact members or arms, of which in the present instancethere-are four, two transmission or line members s s and two testingmembers s s These contact arms sweep over groups of relatively fixedcontacts or terminals, 8", s, s and sirespectively, here shown ashorizontally arranged and being in vertical sets of four, the individualmembers of the sets correspondingto the arms. Said arms are operatedin-the same direction, both in their search tor the wanted terminalsandin the restoration to their initial position, by motor mechanismcomprising a ratchet wheel 8 and a cooperating pawl 3 to the latter ofwhich driving strokes areimparted by successive ienergizations of amotor magnet M. Of the fixediterminals, five active sets are shown, thefirst and fifth being connected by lines L and L to separate substationsA-A, while thesec- 0nd, third and fourth are joined by trunks L, L tothe switch apparatus A ofa private branch exchange. The substation lineshave third conductors L extending from .the terminals's, correspondingto those to which the talking leads are connected, to ground throughcut-oil relays R, R, which, save to furnish a path for current, play nopart in the present invention. The private branch exchange trunks alsoinclude third conductors L with their individual cut-oft relays Rsimilarly grounded; but here the first two of these third conductorsstart at thesecond group of test terminals 8 while the last, :in orderof contact by the switch arms therewith, is joined to the terminal 8 0fits set, or thatin the group to which the third conductors of thesubstations A are connected. Where these third conductors are united tooncior another of the two horizontal test groups. the other testterminal of the vertical set isleft blank. The switch 8,, whenever. itsarms leave their normal position, closes andqmaintains closed until therestoration of :the :arms a contactdevice s r i' To the arms .9 and s ofthe switchttallcing leads or conductors L7, L are joined-these extendingback .throughthe entire chain of or third conductor L when the switch Sis oil normal. At the calling end of the leads L and L is indicated anapparatus C by which the selector actuating and controlling impulses aretransmitted. Many types of these controllers have been invented and usedand it has seemed necessary to here show only enough of the apparatus topro- I vide for the production of four successive conditions to which myimproved connecting mechanism will respond to perform its variousfunctions. Such conditions are furnished by the cooperation of a pair ofmovable arms 4), connected to the talking leads, with four pairs ofterminals w, :0, y and .2. In the first or normal position we, bothsides of the line are open; in the second position as, pulsations ofcurrent from battery B are sent over the lead L to effect the advance ofsome one of the series of selectors to the proper terminals; in thethird a, ground is applied to the lead L to give a circuit transfcrringthe action to the neXt apparatus of the series, or, if this be theconnector, starting its testing and connecting operations, and in thefourth position 2, or that during which the conversation may be carriedon, lead L is grounded while L is connected to battery B Associated withthe switch S by means of a system of local conductors, which willhereinafter be more particularly mentioned, and which are joined to theswitch arms and to the leads L and L and the third conductor L", areshown a pulsator or intermittent circuit maker P, a ringing generator G,busysignal mechanism g and a battery, this latter, for convenience inillustration, appearing at a number of places and being designated bydifferent reference characters.

Forming a part of the connecting apparatus is local controllingmechanism furnished by siX relays. Of these, relay R responsive to thethird position 2 of the controller C after the motor magnet N, under theinflu ence of the pulsations transmitted during position :c, has driventhe switch arms to the set of terminals belonging to the wantedsubstation line or the first trunk of the private branch exchangeapparatus, prepares the circuits for the operation of the other relays.Relay R which is sluggish and which may be termed the connecting relaysince it more directly initiates the operations leading to thecompletion of the connection, when the selected substation line or trunkis not busy closes a portion of the ringing circuit from generator G,operates the cut-off relay R of the line and establishes a busycondition which prevents the appropriation of said line by some otherswitch in the multiple group with S The ringing circuit is completed bya relay R which also prepares for the return of the switch arms to theirinitial position when the conversation has been com pleted. Relay Rwhich is provided with two windings, establishes the talking circuitwhen the called subscriber responds to the ringing of his bell. If abusy substation line is selected, or a private branch exchange chosenand the last trunk reached, relay R or substation test relay, connectsto the lead L the busy-signal mechanism, prevents the operation of therelay R and cooperates with relay R to secure the return of switch armsto zero. Upon the selection of a private branch exchange and the findingof other trunks than the last busy, the private branch exchange testrelay R similarly prevents the operation of relay R and closes thecircuit of motor magnet M to produce a continuation in the advance ofthe arms until an idle, or the last, trunk of this group is reached, inwhich case either relay R or R comes into play as just indicated. Whilethe connection of the relays with the leads, switch arms and associatedmechanisms will be completely developed in the description of operationof the system, it is desired to here call attention to a relation of thevarious elements which is of especial importance. Thisis, that theenergizing circuit of relay R from a ground provided by relay R tobattery B and including conductors 23, 25 105 and 27, is controlled inthe contacts of both .test relays R and R and that the windings of thetest relays are joined in multiple from the ground at relay R byconductors 40, 42 and 44, and 40 and 46 to the groups of terminals s and8 respectively, through contacts of the connecting relay R and the testarms .9 .and s of the switch. Consequently,

if the test arms do not find battery at either test terminal of theselected set the connecting relay will operate and open circuits of thetest relays, but if, on the other hand,'either arm comes to rest upon aterminal to which potential is applied, one or the other of the testrelays will attract its armatures before the sluggish connecting relaycan operate, thus breaking the circuit of the latter. The importance ofthis will appear shortly.

In considering the operation of the system there will first be describedthe connection with a non-busy line, this being equally aplicable to asingle-line substation or to the rst of the plural trunks of a privatebranch exchange. When, in response to the operation of the controllingapparatus C in its secwill reach the terminals of the substation.

ond position, the connecting switch S is selected by a switch S of thepreceding group, a circuit is closed from battery B through lead Lconductor 10, armature 11 and its back contactin relay R conductor 12,back contact and armature 13 in relay R, conductor 14, back contact andarmature 15 of relay R conductor 16, including winding of motor magnetM, back contact and armature 17 of relay R to intermittent ground at thecircuit maker P. Each time that the circuit just traced is closed, motormagnet M is energized and drives the arms s 8 s and s of the switch Sstep by step from one set of its fixed terminals to the next. Thecontrolling apparatus having provided for the necessary number ofpulses, the arms close their front contacts and there is now a path fromground through armature 21, conductor 23, armature 24 and its backcontact in relay R, conductor 25, armature 26 and its back contact inrelay R conductor 27 and winding of relay R to battery B If the selectedline is not in use relay R is energized and opens the back contact ofits 40.

armatures 17, 28 and 29 and closes their front contacts and that ofarmature 30. Armatures 23 and 29 connect battery B to test arms s sallowing current to flow through these arms to the cut-oil relay R bythe third conductor L or L, depending upon whether the selected line isto an or 'dinary substation or is a private branch exchange trunk.

Armature 17 closes a path from the intermittent ground at P throughconductors 31 and 32, spring 33 and Winding of relay R conductor 34 andoil normal contact device 8 of switch S to battery The closing of thiscircuit energizes relay R which by means of its armature 35 looks itswinding to a permanent ground and disconnects it from conductor 32 atthe spring 33. Armature 15 of relay R separates the winding of motormagnet M from conductor 14, through which it has been receivingselecting pulses, and joins it to conductor 34 in preparation for therestoration of the switch arms to zero. Armature 36 of relay R closesthe ringing circuit from generator G, including armature 30 of relay It,conductor 37 through one winding of relay R, spring 38 of said relay,lead L arms s of the switch, limb L of the selected line, ringingcircuit of the substation set, limb L of the line, arm 8 of the switchand lead L to a ground which, in the final position 2 of the controllingapparatus C, will have beensubstituted for battery B upon this side ofthe line. As this circuit includes the high resistance coils of theringer of the called subscriber's set, relay It" does not receivesufficient current to energize it until the subscriber, by taking hisreceiver from the hook, short circuits the ringer. Then relay R attractsits armature 39, which locks the relay by current from battery B throughits second winding, conductor 40 and armature 22 of relay R to ground.It also disconnects at spring 33, the lead L from the first-mentionedwinding of relay R and at spring 4-1 closes said lead L The transmissioncircuit is now complete, talking current being supplied from the batteryB at this time connected to the lead L At the termination of theconversation both sides of the line are opened at the calling end by acondition represented by the normal positionw of controller 0. Thiscauses the release of the switch S which removes battery B from thecircuit of relay R of the connector. The consequent falling 011 of thearmature 21 opens the circuit of relay R and armature 17 is thenretracted. Since relay R is still energized, we have a circuit from theintermittent ground of pulsator P tobattery B through conductor 16 andthe winding of the motor magnet, armature 15 and its front contact inrelay R conductor 34 and contact device 8 The resulting pulses ofcurrent drive the switch arms forward until they reach their normalposition, when the opening of the contact 8 breaks the motor magnetcircuit and that of relay The connecting apparatus is now ready foranother selective operation.

Now suppose that a single line to a substation A is wanted and that itis already in use. When the arms 8 s and s of the switch have beenbrought to rest on the terminals connected to conductors U, L and If 01"the desired line, the terminals .9 of the private branch exchange groupwith which the arm 8 is in contacthaving no connection in thissubstation set, relay R is encrgized as just described. This relay willnot only complete at its armature 21. the circuit of relay R but willalso close a circuit from ground through its armature 22, conductors 40and 42 winding and spring 43 of relay R conductor 44, back contact andarmaturo 29 of relay R arm 8 of the switch and the third conductor L ofthe busy line to a battery, corresponding to B placed thereon by the armof the switch which is already in :possession of the line. By means ofthis circuit relay R is energizedibefore sluggish relayR has had time toopen the circuit of R at the back contact of armature 29. Relay Rtherefore operates and its armature 45 locks the winding of this relayto battery B making it independent of the path to battery given by thearm 8 and the third conductor of the busy line. Armature 11 of relay Rdisconnects lead L from conductor 12, and therefore from the motormagnet and unites it to the mechanism G which operates a busy signal atthe controlling end of the circuit which leads to ground through arm 1)which at this time engages terminal 2. Armature 26 of relay R opens thecircuit of relay R thereby preventing its operation, and closes a pathfrom ground to battery B through armature 21 and its front contact inrelay R conductor 23, armature 24 and its back contact in relay R,conductors 25, 31 and 32, spring 33 and winding of relay R conductor 34and off normal device 8 As previously set forth, relay'R locks itself bymeans of armature 35 and closes the front contact of itsarmatures 15 and36. As relay has prevented relay R from being energized, there is now apath from the intermittent ground at P to battery B through armature 17and its back contact in relay R conductor 16, winding of motor magnet M,armature 15 and its front contact in relay R conductor 34 and off normaldevice 8 The motor magnet is therefore energized intermittently andadvances the switch arms until they have made a complete revolution,that is, have arrived at their initial position. Then the off normalcontact opens and battery B is disconnected from the cir-' cuit of themotor magnet to stop the advance of the switch arms. Relay R issimultaneously deprived of battery Relays R and R remain energizeduntil, in response to the busy signal at the controlling end, battery Bis removed from the lead L by the release of the selecting train. Whenthis takes place, relay R is denergized and in turn releases relay uponopening the front contact of armature 22. The apparatus is now incondition to effect a new connection.

If, instead of a single substation line, the busy line selected were thefirst of a group 0, trunks leading to a private branch exchangef the arm8 would come into contact with the terminal 8 of the third conductor ofthe selected trunk, since for this and all but the final trunk theterminals 8 are blank, while the terminals 8 are connected. So in thiscase, when relay R has been operated, we have simultaneously with theclosing by its armature 21 of the path from ground to battery B throughthe winding of relay R a second path from ground by armature 22,conductors 40 and 46 through winding of relay R, back contact andarmature 28 of relay R arm 8 and third conductor L of the selected busytrunk to battery placed thereon by the arm'of the switch which hasalready selected the trunk. By this circuit relay R will be energizedbefore sluggish relay R has time to attract its armature 28. Armature 24of relay R then opens its back contact, thus stopping the flow ofcurrent from battery B through the winding of relay R to the groundconnection at armature 21 of relay R Armature 13 of relay R opens itsback contact, which is in the circuit of the motor magnet and shunts itswinding by a path from conductor 46 through conductors 47 and 14, backcontact and armature 15 of relay R conductor 16 through the winding ofthe motor magnet, back contact and armature 17 of relay R to groundthrough the intermittent contact maker P. Thus we now have from arm 8two paths through which current flows from the battery connected to theterminal 8 of the busy set through the winding of relay R to a permanentground and through the motor magnet to the intermittent groundconnection at P. Relay R will therefore remain energized, and the armsof the switch will be driven forward until arm 8 makes contact with theterminal of a trunk, the third conductor L of which is not connected tobattery, that is, which is not busy; or until the arms arrive at thelast trunk in the particular private branch exchange group, where thethird conductor is joined to a terminal 8 In either case motor magnetand relay R will be deenergized and the circuit of relay R closed by thearmature 24 at its back contact. If the arms come to rest upon theterminals of a non-busy trunk, relay B would operate and the connectionwould be established as in the case first described of selecting anon-busy line. If, upon the arms reaching the last trunk, this too werefound busy, then arm s would receive current from the terminal 8Therefore the conditions just described with reference to a busysubstation line would be secured, and relay R would operate to cause theapplication of the busy signal and the restoration of the switch.

I claim as my invention;

1. An exchange system comprising switching mechanism provided with aplurality of groups of relatively fixed line contacts, an

independent movable contact member for co' operation with all of thecontacts of each group, telephone lines adapted for one class of serviceand being connected to only one group of contacts, and telephone linesof another class not connected to said last-named group but connected toa different group of contacts.

2. An exchange system comprising a switching mechanism provided with aplurality of groups of relatively fixed line terminals, an independentcontact member for cooperation with all of the terminals of each group,telephone lines adapted for one class of service and having conductorsconnected only to one group of terminals, and telephone lines of anotherclass having one or more conductors connected only to a different groupof terminals and one connected only to the group just mentioned.

3. The combination with a telephone switching mechanism provided withtransmission line terminals and two groups of testing line terminals andwith independent movable members contacting with the respective grou sof testing terminals, of substation lines iaving third conductors connected to one group of test terminals, and groups of trunks with theirthird conductors corlinected to the other group of test termina s.

4. The combination with a telephone switchingmechanism provided withtransmission line terminals and two groups of testing line terminals andwith independent movable members contacting with the respective grou sof testing terminals, of substation: lines iaving third conductorsconnected successively to one group of test terminals, and groups oftrunks with their third conductors connected to the other group of testterminals but with the final trunkof each trunk group joined to thegroup of terminals with the substation lines.

5. In a telephone connecting apparatus, the combination with switchingmechanism provided with a plurality of groups of terminals andindependent movable contact members cooperating with separate groups, ofcontrolling means connected to one group of terminals whereby successivetests of busy terminals are secured, and means connected to anothergroup of terminals for governing the restoration of the movable contactmembers to their normal position upon their cooperation with the firstbusy terminal" 6. ,The combination with a switching mechanism providedwith a plurality of movable testmembers, of busy signal mechanism andringing mechanism, means for controlling thei busy signal mechanismthrough one of the test members, and means for controlling the ringingmechanism through a plurality of the test members.

7. A telephone system comprising a central station, substation lines andgroups of trunk lines extending thereto, a selecting switch havingmovable contact members and separate groups of terminals to the latterof which conductors of the substation lines and trunks are respectivelyjoined, motor mechanism for the selecting switch, and test relays forcontrolling the motor mechanism and being connected in multiple to thegroups of terminals.

8. A telephone system comprising a central station, substation lines andgroups of trunk lines extending thereto, a selecting switch havingmovable contact members and separate groups of terminals to the latterof W iich conductors of the substation lines and trunks are respectivelyjoined, motor mechanism for the selecting switch, test relays forcontrolling the motor mechanism and being connected in multiple to thegroups of terminals, and a sluggish connecting relay in circuit with thecontacts of both test reays.

9. A telephone system comprising a central station, substation lines anda group of private branch exchange trunk lines extending thereto, aselecting switch having movable contact arms and separate groups ofterminals, to the latter of which conductors of the substation lines andprivate branch exchange trunks are respectively joined but with aconductor of the last trunk united to a terminal in the substation linegroup, motor mechanism for the selecting.

of June 1907.

EDWARD O. MOLINA. Witnesses:

GEO. WILLIS PIERCE, JosEPn A. GATELY.

